Date of Completion


Embargo Period



Sunil Wadhwa, DDS, PhD; Ivo Kalajzic, MD, PhD

Field of Study

Dental Science


Master of Dental Science

Open Access

Campus Access


The phenomenon of orthodontic relapse adds time, cost, and frustration to an orthodontic case. Little is known about the biological basis of relapse. Proper characterizations and quantification of osteoblast differentiation in a mouse model of orthodontic relapse have yet to be demonstrated. It is the goal of this study to characterize and quantify osteoblast differentiation in orthodontic relapse in an in vivo transgenic mouse model. Transgenic mice with GFP bound to Bone Sialo Protein (BSP) promoter marker, a protein expressed by early osteoblast lineage cells were used. It is hypothesized that GFP-BSP will be decreased on the compression side of the furcation of the mouse maxillary first molar when compared with the contralateral control molar in both orthodontic tooth movement and relapse. Nineteen 10-12 week old mice were divided into two groups: 1.) 2 weeks of OTM applied by spring, 2.) 10 days OTM followed by spring removal and 4 days of relapse movement. TUNEL staining was performed to evaluate apoptosis. Results show a marked decrease in BSP-GFP on the compression side and tension side after 2 weeks of OTM. A significant decrease was also seen on the compression side after 10 days of OTM and 4 days relapse. There was a significant increase in apoptosis on the compression side after OTM but not after relapse.

Major Advisor

Flavio Uribe, DDS, MDS